Darkness Falling
by alightintheshadows
Summary: Alois wants to play a game with Ciel and Sebastian, and he meets someone that can help him. After his butler is captured, Ciel has to find a way to get him back without giving himself up to Alois. Who is this new friend of Alois, and why does she want revenge against Sebastian? And how is Undertaker involved? Rated T just to be safe.
1. Chapter 1

**Hello! This is my first multi-chapter fanfic for Kuroshitsuji and I hope you all like it! While it is a multi-chapter fic, it will still be fairly short. I always saw Alois as a very theatrical character, so that's why I made his plan fairly dramatic. Anyways this is set in the anime, just a few days after Ciel and Alois officially meet for the first time. Basically, Ciel declined the invitation that Alois sent him to visit the Trancy manor and the deal between Claude and Sebastian didn't happen, for this story's purposes.**

 **I do not own Kuroshitsuji or its very sexy characters.**

The dark streets of London were relatively quiet on this cool evening. Ciel and Sebastian were patrolling the streets as they made their way to the River Thames, looking for a serial killer that had murdered five teenage boys in the span of just a few days. Ciel had just gotten word from the Queen this morning, and he and Sebastian immediately began working on the case. After stopping by the Undertaker's funeral parlor, he learned that each of the victims had a pentagram carved into their chests. The victims' bodies had been found along the river in various places, so Ciel and Sebastian were hoping to catch the killer dumping his next victim. Of course this wasn't ideal, but the victims had all been taken from random places around London. Finding him at the river would be their best chance at catching him. Ciel honestly was enjoying the silence, that is until it was rudely interrupted upon reaching the river.

"Bassy!"

The young earl and his butler were greeted with the sight of a blur of red hurdling its way toward Sebastian, who dodged it with ease.

"Oh great, you again," Ciel mumbled as the grim reaper got up from the ground. "Why is it that you seem so insistent upon assaulting my butler?"

It took Grell a minute to recall that Ciel no longer remembered him. He brushed himself off and approached the two.

"I have just collected a couple of souls from my to-die list and didn't expect to run into you two here," he explained, "I couldn't pass up an opportunity to see my Bassy!"

Sebastian fought the urge to groan. Sometimes he could get very annoyed with the flamboyant reaper, but he could actually be helpful on occasion. He sighed before addressing Grell.

"I am afraid my young master and I are a bit busy at the moment," he replied smoothly.

He turned with Ciel to continue patrolling around the river when Grell's voice caused them to pause.

"I am assuming you both are here about the string of murders occurring over the past couple of days that I heard about?"

Ciel raised an eyebrow at the reaper.

"Would you happen to know anything helpful about that?" he asked.

Grell simply shook his head. Suddenly, Grell had a confused look on his face. Sebastian tensed up next to Ciel, which the young earl immediately noticed.

"Sebastian, what is it?" he asked.

"I am sensing the presence of other demons. From what I can gather, it looks as if Claude Faustus and the triplets have decided to join us."

"From the Trancy manor? They were hardly a match for you."

Sebastian seemed to ignore Ciel's comments and looked to Grell.

"I know you sense it as well. Do you know what it is?"

Grell shook his head again, slightly concerned by the worried expression on Sebastian's face. Much like demons, grim reapers could normally sense when other supernatural beings were nearby. Especially ones of great power. There were some exceptions, but they could usually determine what being it was.

"Sebastian?" Ciel asked, not liking how tense his butler had now become.

"Whatever it is, it's getting closer," Grell commented.

Sebastian needed to act quick. He didn't know what was coming, and he had to protect his young master. He grabbed Ciel's shoulders and guided him over to the grim reaper.

"Grell, I need you to get him away from here. I'll do anything you want if you just take him somewhere safe."

Sebastian knew that he was going to regret that, but he didn't have much of a choice right now. Grell nodded, at a loss for words. He had always seen Sebastian as confident, having full faith in his abilities to follow his master's orders and protect him. This creature that was coming must have him extremely worried if he was willing to trust him with the young earl. Ciel shrugged Sebastian's hand off his shoulders.

"I refuse to go anywhere with him!" Ciel shouted as he pointed at Grell.

Sebastian sighed. He had always known Ciel to be a very stubborn child, but he didn't have time for this.

"Please, my lord. I know I can handle the demons, but there is something else with them. It has a power unlike anything I have come into contact with in centuries. Claude and the triplets can already sense that I am here, so they will follow me if I go with you. My top priority is to protect you, so let me," he said as he knelt down so he was eye-level with Ciel, "Go with Grell, and I will find you two the moment I get the chance."

Ciel could see it in Sebastian's eyes that he was actually scared. He found that fact alone to be unsettling. He nodded, and Sebastian visibly relaxed. He nodded to Grell, who then scooped up the young earl in his arms.

"Sebastian," Ciel said before they took off, "You better come back to me. That is an order."

The demon grinned and bowed.

"Yes, my lord."

Grell jumped and soared through the air until he landed on top of one of the nearby buildings. Once they were out of Sebastian's sight, Ciel squirmed his way out of Grell's arms and ran to the edge of the building. The reaper was immediately at his side.

"I will go with you if the situation escalates, but please let me watch for now."

Not wanting to disobey Sebastian's orders, but also not wanting to bother arguing with the young earl, he simply nodded. Not even a minute later, they saw Sebastian being approached by Claude and the triplets.

Sebastian could sense that Grell was still nearby. Knowing his master, he probably demanded to watch what was going on. At least if it really came down to it, Grell could overpower Ciel with no problem and get him somewhere safe. He didn't move away from the river as Claude and the triplets arrive. He could sense that the unknown creature was nearby. It seemed like Claude didn't want it to show itself quite yet. Despite it getting closer, he still couldn't begin to gauge what it could be, and that absolutely terrified him. However, he didn't let that affect his calm and collected outer appearance. After all, what kind of butler would he be if he allowed himself to show any ounce of fear in front of an enemy?

"No wonder Trancy manor doesn't look as it should. How can it when the servants are not even there?" Sebastian remarked with a smirk.

"Always good to see you, Sebastian," Claude responded dryly, "It was a shame that Earl Phantomhive did not accept my master's invitation."

Sebastian remembered the invitation for him and Ciel to go back to Trancy manor. That had arrived a week ago, and Ciel had decided to decline. After first meeting Alois, Ciel was not exactly ecstatic to meet with the deranged child again anytime soon. Claude continued before Sebastian could even respond.

"I am afraid my master took that quite personally. He ordered us to bring you to the manor."

"How kind of you to offer," Sebastian said with false politeness, "But I will have to decline yet again. You see, my young master and I are currently looking for a murderer here in London. Perhaps we could join you another time."

He could sense the creature creeping even closer to the group of demons. He risked a quick glance around, but saw no sign of it. When he looked back to Claude, he had a smirk on his face.

"I don't think you will have to worry about any more murders."

Sebastian couldn't hide the look of shock that crossed his features. So Claude was behind the murders? That must have been a ploy to lure him and Ciel away from the manor. The smirk on Claude's face grew more sinister.

"And that was not exactly an invitation. We have strict orders to bring you back with us that we plan to fulfill. It would be more convenient if Ciel was here as well. He would have been more than welcome to come with us, but you were the only one we are under orders to take. Ciel will be joining us soon, anyway."

Sebastian stood his ground, his eyes narrowing at the four demons before him. He tried to keep up his aura of confidence, but it was starting to fade as he sensed the powerful being getting closer and closer. Claude seemed to notice.

"I know you sense her, Sebastian."

The Phantomhive butler was angry. It had been hundreds of years since he even remotely felt fear, and now not only was he feeling it, but the other demons could tell. Before any of them could react, he reached into his tailcoat for his knives and flung them at the triplets. Since they were not near as fast as he was, they weren't able to dodge the attack and the knives impaled them to the ground. Claude ran at him for an attack. The Trancy butler tried to punch, kick, and anything else to briefly incapacitate Sebastian, but he was unsuccessful. Sebastian dodged Claude with ease, that is until something tackled him and he was sent flying through the air and he crashed into a nearby building.

Sebastian quickly got to his feet and looked around to see what had collided into him. He nearly jumped when he felt a hand on his shoulder. He whipped around and came face to face with a beautiful woman in a white long-sleeved dress with black hair that went down to her waist. Sebastian's eyes widened. It looked as if he'd seen a ghost. The woman smiled when she saw the effect she was having on the demon.

"There is no possible way you can be here," he muttered, backing away from her.

"Sebastian Michaelis, I hear that is what you are going by now. It has been a while," she said seductively.

Two of the triplets had already recovered from Sebastian's attack, each of them grabbing one of his arms. Claude appeared behind him, wrapping an arm around Sebastian's waist and yanking his head back to expose his throat. The woman sauntered up to Sebastian who was putting up a fight with the demons restraining him. Knowing that they wouldn't be able to hold him for long, she exposed her razor sharp teeth and sunk them into his neck. The unexpected action caused Sebastian to cry out in pain, especially when she began to drink his blood greedily. His vision started to blur, and his knees buckled as more blood was forcefully sucked out of him. If it wasn't for the demons holding him up, he would have collapsed to the ground. He let out a groan as he felt consciousness fading, which he knew wasn't good as demons can rarely be rendered unconscious. He barely even registered Claude and the two triplets dropping him. They all loomed over him with satisfied looks on their faces. His eyes fluttered shut, and he was greeted with darkness.

Ciel hated being so far away from his butler. He couldn't tell what Claude or Sebastian were saying. He wasn't surprised when he saw Sebastian quickly incapacitate the triplets and engage in combat with Claude. He was shocked when he saw a woman appear out of nowhere and collide into his butler.

"What are you doing here?" he heard Grell ask someone, but he kept his eyes locked on Sebastian.

As quickly as she showed up, she disappeared. He saw Sebastian looking around, and she appeared behind him. When he didn't immediately start fighting back, Ciel knew that something was wrong. He could only watch in despair as the other demons recovered and restrained his butler. What made his blood run cold was when Sebastian cried out in pain. Ciel was about to call out to him, but a hand clamped over his mouth.

He looked behind him to see Undertaker. He put a black-nailed finger to his lips, a warning to be quiet. Sensing that Ciel wouldn't do anything to attract the attention of the others, Undertaker took his hand away. Ciel watched with wide eyes as Sebastian lay on the ground, unmoving. He saw Claude pick him up and tuck him under his arm, as if he weighed nothing more than a rag doll.

In a flash, they were all gone, and they had taken Sebastian with them. Ciel turned to Undertaker.

"What are you doing here?" Ciel demanded, repeating Grell's question from earlier. "Do you know what the creature was and what she did to my butler?"

"If you were wise, Earl Phantomhive, you two would follow meeeee!" Undertaker said as he jumped off the building they were currently standing on.

Ciel nodded to Grell, who then picked him up and followed Undertaker into the night.

 **And there's the first chapter! Sorry if Grell seemed a little out of character, but I wanted him to be unsettled and a bit more serious about something that had even a demon like Sebastian scared. Let me know what you all think!**


	2. Chapter 2

**Here is the next chapter! I hope you guys enjoy it. This chapter will explore a little more into what Undertaker's role will be in this story as well as what Alois is planning. Also this is obviously in the anime universe, so Grell knows that Undertaker is a legendary grim reaper since that was revealed in the first season. Just thought I might mention that to prevent confusion later on.**

 **I still do not own Kuroshitsuji.**

The silence that Ciel had found so relaxing previously now only served to annoy him. As he and Grell followed Undertaker throughout the city, many questions ran through his mind. He knew that his informant knew something about that creature. He also probably knew what happened to his butler. In all the time that Ciel had known Sebastian, he had never seen the demon lose a fight with anyone. If that creature could render him unconscious, who knows what else she could do.

"Are we going to your funeral parlor?" Ciel demanded, finally breaking the silence.

Undertaker laughed as they made their way down a familiar street.

"Where else do you think I would take you, young Earl? It is the safest place for you, after all," he responded.

Ciel was confused. Of all places he would have considered safe, Undertaker's funeral parlor was definitely not on the top of that list. Undertaker quickly unlocked the door and ushered him and Grell inside. As soon as the door was shut, Ciel opened his mouth to begin demanding answers again, but he was interrupted by his quirky informant.

"Why don't you relax and take a seat, my lord?"

Ciel felt a mix of anger and shock.

"How can you possibly expect me to relax when my butler was just attacked and abducted? You still have yet to answer my question of what that creature even is!"

Undertaker chuckled.

"Impatient, are we?" he observed as he led Grell and Ciel to the back of his parlor. He pulled out a few books before speaking again. "That woman's name is Gwenna. I found her in an alley just over a week ago and I brought her here. She wasn't able to remember anything but her name. Since I offered her food and shelter, she allowed me to study her. Due to my extensive knowledge on supernatural creatures, I was able to determine that she was an archdemon."

Ciel looked absolutely shocked. He knew that his informant knew quite a bit of useful information, especially concerning the cases that he solved. However, he wasn't aware that Undertaker even knew about supernatural beings.

"So, how did this archdemon know Sebastian?" Grell asked.

Undertaker shrugged.

"I honestly couldn't tell you. Considering the fact that she is a demon, an extremely powerful one at that, she has probably run into him at some point previously."

Ciel's head snapped to look at Undertaker.

"You know that my butler is a demon?" Ciel hissed.

Again Undertaker chuckled, but it wasn't the usual mad laugh that Ciel had begun to associate with him.

"Of course I did, my lord. Anyways, I had never actually encountered an archdemon, so I immediately began researching anything I could find about them. I prefer to know everything about the powers of any supernatural being that I might come into contact with, as well as how to kill it should the need ever arise. I have learned that she is faster and stronger than any other demon, and her power will increase if she drinks the blood of other demons."

Ciel stared dumbfounded at his informant and shook his head. It was almost too much to process. Having been quiet for a while, Grell finally spoke up.

"So how do you kill an archdemon?" he asked.

Undertaker's mouth was set into a grim line as he opened one of the books.

"Unfortunately, it is nearly impossible to kill an archdemon. However, there is a way to trap one in hell. It's a potion of sorts. From what I understand, just mere contact with it will set her aflame and send her right back to hell. We can go get your butler as soon as I get the proper ingredients and prepare the potion, Earl Phantomhive."

"You would actually help me? Why?" he asked with wide eyes, absolutely astounded.

Undertaker seemed to ignore him and turned to Grell.

"Would you be able to assist me?" he asked the normally flamboyant reaper.

"A chance to work with a legendary grim reaper? I would love to!" Grell exclaimed, immediately perking up.

"Wait a minute," Ciel muttered, looking to Undertaker with wide eyes, "You're a grim reaper?"

Undertaker let a mad smile take over his face yet again. He removed his hat and lifted his bangs. Ciel was greeted with the most stunning pair of eyes that he had ever seen.

"Surprise, little Earl."

 ***break***

"Is he coming around?"

"I do believe so, your highness."

Sebastian groaned as he began the return to consciousness. He registered that he was sitting upright, so someone must have sat him down in a chair. He could hear voices, but he had no idea who was talking to him. None of the voices sounded like his young master.

"I may have drank a little too much of his blood. He should have awaken long before now."

Sebastian's eyes shot open as he heard her speak, instantly remembering what happened. He found his chin resting on his chest, and it took Herculean effort to raise his head. He must still be weak from all of the blood he lost. He was met with the sight of Alois Trancy standing directly in front of him. Hannah and the triplets were standing behind the boy, awaiting any orders that he might have for them.

"Glad for you to finally join us, Sebastian!" the young boy said joyfully.

Sebastian looked around and saw that he was in a dimly lit room, only a few candles providing light. His head threatened to fall back down to his chest, but a hand in his hair kept his head upright. He could see Claude smirking at him out of the corner of his eye.

"Not to worry," Alois continued, "Ciel will be coming soon! I know that you can't stand to be separated from your master for very long."

"Why did you not just take us both?" Sebastian managed to ask.

Anger glazed over the young boy's eyes. He stepped closer to the weakened demon, icy blue eyes boring into Sebastian's.

"You destroyed my village. I want to see you suffer. I want to see the look on your face when you see Ciel come here for you, only to have his soul made unattainable to you."

Sebastian was genuinely confused. He had heard of a demon destroying a village years previously, but he had no idea how Alois came to the conclusion that he was the one who did it.

"I had nothing to do with-"

Sebastian was cut off when Alois struck him across the face. Apparently telling the truth was going to get him nowhere with the deranged boy. He sighed and shifted in his seat, noticing that he was actually hardly able to move. He looked down and saw his wrists and ankles bound in chains decorated with ancient markings.

"Do you like your restraints, Sebastian?" he heard a feminine voice asked, "As you know, they can only be forged in hell, where I have been trapped for the last seven hundred years thanks to you."

He turned his head toward the voice. Sure enough, the woman in the white long-sleeved dress was standing in a corner, watching him almost hungrily. The woman that he hadn't seen in seven hundred years and was secretly hoping he would never see again.

"Good to see you again, Gwenna," Sebastian responded dryly, completely ignoring her previous question.

The archdemon looked unamused as she moved to stand next to Alois.

"I think you have the wrong idea, Earl Trancy," Sebastian began, "My young master won't be coming for me. That would require too much effort on his part. What exactly do you think you will gain by keeping me here?"

To Sebastian's surprise, Alois laughed and Claude looked like he was having trouble hiding his amusement. The Trancy butler pulled out a photo from his pocket and handed it to his master, who proceeded to show it to the captive demon. His eyes widened in shock. It was the photo that he had taken of Ciel. The photo that proved that he was the one the young earl cared about most.

"Where did you get that?" Sebastian demanded.

"That isn't of any importance. What matters is that this is proof that Ciel cares about you. As long as I have you here, he will most certainly come for you."

Sebastian stared at the photo. He realized that the saddest part was that Ciel wouldn't even remember this picture. However, something still didn't make sense to Sebastian.

"How exactly are you involved in all of this, Gwenna?" he asked.

The archdemon let a smile cross her features.

"Let's just say that Ciel isn't the only one driven purely by revenge," she said, then she turned to Alois, "Would it be acceptable for me to have a bit of fun with our prisoner?"

A sadistic smile spread across the deranged boy's face. He nodded and motioned for the rest of his servants to follow him, leaving Sebastian and Gwenna alone. Considering the look that the archdemon was sending his way, Sebastian knew that this was not going to be a pleasant experience for him. His thoughts were confirmed when she traced the bite mark that she had inflicted on him earlier, then sank her teeth into the wound. Sebastian's cry of agony rang throughout the silence of the Trancy manor, bringing nothing but satisfaction to the occupants within.

 **Well there's the second chapter! Next chapter will dive more into the past between Sebastian and Gwenna. Anyways, let me know what you think!**


	3. Chapter 3

**Here is the next chapter! Thank you to for following/favoriting/reviewing this story! It means a lot! Sorry for the longer wait. The beginning of my summer has been pretty crazy. I'm hoping updates will come more consistently.**

 **I do not own Kuroshitsuji.**

Ciel woke up with a crook in his neck. He was stunned to find himself in Undertaker's funeral parlor, that is until he recalled the events of the previous evening. He remembered Undertaker offering him a coffin to sleep in for the evening, but he had refused and wound up falling asleep in a chair. He heard humming and went to investigate. He was met with the sight of the legendary reaper organizing various ingredients and flipping through books. His silver fringe was in front of his face yet again, concealing his eyes.

"Good morning, Earl Phantomhive. Did you sleep well?" Undertaker asked with a chuckle, not looking up from what he was doing.

"Yes, very well," the young earl muttered sarcastically. "Are those the ingredients for the potion?"

Undertaker nodded.

"There was one ingredient that I didn't have, and I sent Grell out to go fetch it. Once I have it, I should have the potion ready by this evening and we can go get your butler."

"You know," Ciel began, "You never answered me last night when I asked why you would help me."

The silver-haired reaper stopped what he was doing and looked at Ciel.

"Normally, I would consider myself a neutral force. I don't side with anyone whether it be demons, angels, grim reapers, or anything else. I prefer to avoid conflict as much as I can, but in a way I feel responsible for what happened to Sebastian. From the first time I met him, I could sense that he was a powerful demon. The only reason an archdemon would be anywhere near London would be because it had business to do with your butler. When Gwenna came to stay with me, I should have been more careful. Even though she lost her memories, I should have taken more precautions for the moment they came back to her."

Ciel was actually surprised that Undertaker was putting the blame on himself. He really didn't have a reason to. How was he supposed to know that Gwenna would regain her memories and join forces with his enemy? While he didn't think that the grim reaper was to blame, he didn't say it. He couldn't let anyone think that he had any sort of a soft side.

"So what exactly is the plan then?" he asked.

"From what I could hear, Earl Trancy is expecting you to go to his manor to get Sebastian. Grell and I will go with you. I will not kill the others. I personally have no reason to and it is not my place. It could potentially raise the tension between demons and grim reapers because it would seem that I meddled in some affairs that I had no business in, which would cause more problems than I care to deal with. However, I will incapacitate them long enough for me to send Gwenna back into hell and for us to get away with Sebastian."

Ciel nodded. It would honestly be much easier to just kill Claude, Hannah, and the triplets. However, Undertaker didn't have to help him at all, despite him feeling like he had to. He certainly wasn't going to complain. Besides, Sebastian had proved that he could take on the others. He could certainly do it again. He was holding his own quite well against Claude and the triplets until Gwenna got involved. Undertaker turned back to whatever he had previously been doing before Ciel had awaken.

"Is there anything I could help you with?" the young earl asked.

Undertaker was obviously caught off guard. Ciel could see one of the eyes peek out from behind the silver bangs, looking at him curiously.

"How interesting," he observed, "I have never known any nobleman to have any desire to help me with anything. There isn't really anything you could do for me."

Ciel sighed and continued to watch Undertaker do his work. There was an awkward silence between the two until the grim reaper broke it.

"I do have a question, if you wouldn't mind answering it for me: if you didn't have my help, would you still go after your butler?"

The young earl was taken aback by the question. He hadn't expected his informant to ask such a thing. Nevertheless, he nodded. It was true. He would have gone to the Trancy manor. It's not like he didn't know who took his butler, after all. Undertaker chuckled to himself. Much to Ciel's surprise, it wasn't his usual mad laugh.

"I should have figured. The Phantomhive's have never disappointed me in terms of entertainment."

Undertaker immersed himself in preparing the potion, and Ciel let him be. He thought about asking the quirky reaper what he meant, but figured he should leave him to his own devices. The quicker Undertaker was able to finish the potion, the sooner he would be reunited with Sebastian.

 ***break***

Sebastian grunted as the knife plunged into his stomach yet again. Gwenna had decided that she would show him the weapons she had forged during her long stay in hell, and it had not been a pleasant experience for him. Not in the slightest. She yanked the knife out then traced up his chest to under his chin with it, tilting his head up.

"It's a shame you don't scream anymore. I rather enjoyed it when you did," she commented with a smirk on her face.

She scratched her nails down Sebastian's pale chest, having cut off his tailcoat and shirt earlier. He would like to say that he didn't scream because he didn't want her to have the satisfaction of hearing it. The truth is that he actually lost his voice a while ago, which he wasn't even aware was possible for a demon. Gwenna was relentless in her methods of torture, slicing and stabbing him wherever she could. It was as if she was an artist. Her knife was her paintbrush while Sebastian was her canvas, the end result being a bloody masterpiece.

"I'm sorry to disappoint you," he managed to rasp out, blood trickling out of his mouth.

She straddled his thighs and took his face in her hands. His eyes were slightly glassy from all of the blood loss, but he was still completely coherent.

"You know you wouldn't be in this situation if you hadn't turned on me. We could be gorging on souls together, but you had to go and trap me. That wasn't very nice of you, Sebastian. I suppose I should have known. Demons aren't exactly known for being kind."

Sebastian involuntarily winced as she moved down to his neck, expecting her to bite him and drink his blood again. Much to his surprise, she trailed kisses up his neck and along his jaw. She stopped when her lips were right next to his ear.

"Didn't you miss me? Didn't you miss _us_?" she asked, "Your betrayal really hurt me, but I guess I could forgive you if you wanted to join me again. Just think of what we could do."

In a way, Gwenna reminded him of Angela. Both were determined to do whatever it took to fulfill whatever vision they saw for the world. He was brought out of his thoughts when he felt Gwenna's lips on his own. It felt strange for her to kiss him again. It felt familiar, but extremely uncomfortable at the same time. Sort of like when one sees something that reminds them of a bad memory. Sebastian realized he was basically reliving one now.

He tried to push her away, but she hugged him tightly against her, trapping his bound hands between their bodies. She tangled her fingers in his hair, forcing him to remain lip-locked with her. The fingers on her other hand dug into one of the stab wounds on his back, causing him to gasp in pain. She used this to her advantage and forced her tongue into his mouth.

Sebastian responded immediately by biting down on her tongue. Gwenna shrieked in pain and disgust and finally got off of him. He spat the blood out of his mouth. He smirked at his moment of victory. It was obvious that she didn't expect that much resistance from him. Unfortunately, she wasn't very pleased with him.

"Is Sebastian giving you trouble?" Claude asked.

The Phantomhive butler nearly groaned as Claude walked in to join them. He hated for the Trancy butler to see him in such a weakened state. He could practically feel the smugness of the other demon.

"I'm afraid he is," Gwenna said as Claude moved to stand next to her.

The two exchanged a look, predatory smiles spreading across their faces. Gwenna turned to the table she kept her knives on while Claude moved behind Sebastian. He tensed when he felt Claude's hands on his bare shoulders. He glanced behind him and saw that the smirk on the Trancy butler's face had grown since his little display of discomfort. Gwenna sauntered back over to them with a flask in her hand.

"Have you ever seen the effects of holy water on a demon, Sebastian?"

It was a stupid question. Of course he had, and she knew it. She would use it to torture those who stood in her way. He refused to give an answer. This only annoyed the archdemon. She motioned to Claude.

"Get his mouth open."

Claude gripped Sebastian's jaw, trying to force it open. The Phantomhive butler was stubborn and fought Claude with what little energy he had left. The other demon resorted to throwing him off of the chair he was sitting in, causing him to land on his numerous wounds on his back. He cried out in pain, providing Claude with the opportunity he needed. He gripped Sebastian's jaw again, this time he was successful in keeping it open.

Gwenna loomed over the captive demon, her eyes boring into his fear-filled ones as she poured the holy water into his mouth. Claude clamped his hand over Sebastian's mouth, forcing him to swallow the toxic liquid. It felt as if fire was coursing down Sebastian's throat and down to his stomach. He clawed at his throat as he felt it burn, as if that would do anything to ease his pain. Claude and Gwenna looked amused as Sebastian writhed on the ground.

The Phantomhive butler clenched his teeth to stop himself from crying out, determined not to give his captors any more satisfaction. The burning sensation in his body intensified, making this more difficult. What made matters worse was that there was nothing Sebastian could do until his demonic body purged the holy water from his system. When that would happen, he didn't know. Violent spasms tremored throughout his body. A look of fake pity settled on Gwenna's face. She knelt down next to him and whispered in his ear.

"I would reconsider my offer if I were you, Sebastian. If you don't, I know exactly how to make the rest of your life a literal living hell, and I will start by depriving you of your young master's soul. I am being nice by offering you another chance. Think it through carefully."

Sebastian's thoughts flickered to Ciel. Alois stood firm in his belief that Ciel would come for him. He hoped his young master was as far away from the Trancy manor as he could get. However, after years of serving the young lord, he was well aware that the boy was stubborn and would do whatever he saw fit. He returned to reality quickly as he felt something coming back up his throat. After vomiting a mixture of blood and holy water, he collapsed on his side and his eyes fluttered shut.

His body couldn't take it anymore. It needed rest. The last thing he heard were the dark chuckles of Claude and Gwenna as he quickly faded away from consciousness.

 **And there's chapter three! I hope you all liked it. Next chapter will look a little more into Gwenna's past and how she knows Sebastian. I can't wait to write that part. Anyways, until next time!**


	4. Chapter 4

**Greetings once again! Sorry for the long wait for this update. Anyways, here is the next chapter! This one will explore a little more into Sebastian and Gwenna's past, so I hope you all enjoy that!**

 **I do not own Kuroshitsuji. Just my plot and original character.**

" _Isn't it magnificent?" Gwenna whispered in his ear._

 _He looked upon the army of demons before him, careful not to let his face express what he was truly feeling. He turned his head slightly, a sly smile spreading across his face._

" _I would have to say it is," he answered._

 _Gwenna spun him around for him to fully face her. She crushed her lips to his, and he smiled into the kiss. He fiddled with the vial he kept hidden within his hand._

 _Suddenly, he pulled away from the kiss, throwing the vial so it broke at Gwenna's feet. The archdemon was engulfed in flames. There was a flicker of betrayal that crossed her face before she screamed in a combination of pain and rage._

 _With that, he ran and didn't look back._

A dull burning sensation in his throat was the first thing to pull Sebastian toward consciousness. The only thing he registered other than the immense pain coursing through his body was the hand that stroked his hair. He kept his eyes closed, in a vain attempt to feign sleep.

"I know you're awake, Sebastian."

Initially, he didn't want to open his eyes. His mind changed when Gwenna's hand left his hair and her fingernails dug into the bite mark on his neck. He remained silent, but his eyes finally opened.

Much to his surprise, Gwenna wasn't smirking down at him. She adjusted him so his head was in her lap and she continued stroking his hair.

"Why did you betray me?" she asked with just a tinge of hurt in her voice.

The question shocked the Phantomhive butler. What surprised him the most was the fact that she seemed as if she truly wanted to know. He couldn't believe he had to explain it to her.

She was wrong when she claimed that they could have been gorging on souls together if he hadn't betrayed her. She didn't see reason or logic. She wanted to rid the world of any and all creatures that would get in their way of feasting on souls. However, she overestimated her own power and her army. There was no way her army of demons could annihilate all of the angels and grim reapers.

She would have led them all to their demise.

"You were leading us to our own destruction, Gwenna," he said, his voice raspy, "Neither one of us would even be here if you had gotten your way. Your entire army would have been completely demolished."

Gwenna clicked her tongue and shook her head.

"You should have had more faith in me. However, I do understand your hesitations. I was completely serious when I offered you the chance to join me once again. Although, I guess it really isn't much of a choice."

Sebastian's eyes widened. She couldn't possibly mean….

"I hope it won't come to that," she chuckled, noting his expression, "You are too great of an ally to not have on my side. If you will not join me willingly, I will bind you to me. I will also ensure Claude gets Ciel's soul."

The Phantomhive butler nearly groaned in frustration.

If an archdemon so desired, he or she could bind another demon to them. Similar to Sebastian's contract with Ciel, he would be forced to follow through on Gwenna's every order. From the sounds of it, she would rather he just cooperate with her. However, she was bent on having him by her side no matter what. He shook his head, not able to believe he was in this situation. He didn't even want to think about it.

"You never answered me earlier. How exactly are you involved in all of this?" he asked.

"Alois wants Ciel, but knows he can't have him with you in the way. His staff is unable to help him against you. As much as I hate to admit it, I wouldn't have been able to catch you by myself either. Together, all of us could overpower you, so I offered him my services in exchange for you once he sees Ciel's soul is made unattainable to you. However, I can make sure you can consume your master's soul if you willingly join me."

Sebastian's eyebrow quirked a fraction. He had a feeling that she wasn't exactly loyal to the deranged Trancy boy. She always had her own agenda. However, he didn't exactly expect her to betray him because of his own cooperation.

Claude didn't even give him time to contemplate an answer.

"Earl Phantomhive is approaching the manor," he said, "It looks as if he has brought a couple of guests with him as well."

The Phantomhive butler froze. He had hoped his young master wouldn't come, but a part of him knew the boy would. Ciel was too stubborn for his own good. Gwenna cocked her head to the side.

"I don't think Sebastian is presentable. Would you agree, Claude?"

Claude smirked and nodded. Gwenna didn't need to ask the Trancy butler to get her one of the knives she forged. He grabbed one for her and one for himself. His smirk turned into a malicious grin as he advanced toward Sebastian.

Gwenna moved his head off of her lap and held his bound hands above his head, giving Claude full access to his chest and stomach. The wounds the archdemon inflicted earlier had stopped bleeding, but Sebastian figured Gwenna and Claude were dead set on reopening them. He winced and grit his teeth in pain as the Trancy butler sliced through his previous wounds and made some new ones of his own.

Sebastian shut his eyes, trying to block out the torture being inflicted upon him. He kept his mouth shut, refusing to give either demon the satisfaction of hearing him cry out in pain. He could feel his blood pooling around him. He hadn't even realized Claude stopped carving into him until he was flipped over onto his stomach.

Gwenna perched herself on his lower back. He couldn't help but let out a choked scream as she plunged her knife right in between his shoulder blades, dragging it down his back. She stabbed him so deep that he coughed up blood. She made two more of these deep incisions on both sides of the first.

Sebastian was shaking from the pain and blood loss. Gwenna finally got off him. Claude yanked him to his feet and wrapped an arm around his waist to keep him upright. He glared at Gwenna through his raven hair that had fallen in front of his face, unable to hold his head up on his own. The archdemon tilted it up for him. She looked down at his stomach and slowly took in his appearance until she met his eyes again.

She dipped the fingers on her free hand in the blood that was still flowing down his chest. She traced them across his face, staining it with his own blood.

"There, now you're presentable enough for your master," she said with a grin that definitely tinged on the evil side.

Claude threw the Phantomhive butler over his shoulder, and he and Gwenna made their way through Trancy manor.

Sebastian's world seemed to spin. It wasn't sure if he had ever felt so weakened and hurt in his entire existence. Although, if anyone could put him in this state, it was definitely Gwenna.

He didn't even have the energy or strength to put up a fight, and that angered him. His young master shouldn't see him like this. What kind of butler would he be if he let his master see him so bloody and weak?

"Oh, good! Sebastian has joined us again!" Alois proclaimed.

Claude slid Sebastian off of his shoulders. Unable to stand on his own, the Phantomhive butler nearly collapsed the second his feet hit the ground. Once again, Claude snaked an arm around his waist. He leaned back heavily against the other demon, wincing as he aggravated the wounds on his back.

Hannah and two of the triplets were there, standing by their master. Sebastian heard footsteps coming. The deranged Trancy boy turned to look at him with a smirk that even he would consider quite demonic.

Ciel was coming.

 ***break***

Ciel wasn't sure what he was expecting to see as he, Grell, and Undertaker were led by one of the triplets through Trancy manor. He in no way expected the sight he saw when he was brought to Alois.

"Ciel Phantomhive!" the Trancy boy greeted. "Good to see you finally decided to accept my invitation!"

However, Ciel was paying absolutely no attention to Alois. His eye was locked on his butler.

Sebastian's hands were bound in front him, and Ciel noticed there were chains wrapped around his ankles as well. His tailcoat and shirt was gone, but there was so much blood covering him that Ciel couldn't really see much of his skin. It was obvious his butler was in agony. He could tell that Sebastian wouldn't be standing at all if it weren't for Claude holding him up.

He felt enraged as he saw the satisfied smirk on Claude's face. Gwenna stood next to Claude and Sebastian. Looking at the blood stains that covered her white dress, Ciel deduced she and Claude were the cause of Sebastian's pain and misery.

"What did you do to Sebastian?" Ciel demanded as he took a step forward.

He felt two hands on his shoulders pull him back. Perking his head up, he saw Undertaker shake his head slightly, a silent warning not to do anything rash. Ciel glanced at Grell. The normally flamboyant reaper could only stare at Sebastian with a mix of horror and sadness.

"I thought you knew better, Ciel," Alois commented, "It is rather rude to not even acknowledge your host."

Ciel glared at Alois.

"What is it you want?" he asked through clenched teeth.

"I just merely want to talk with you! If you had just accepted my invitation earlier, we could have avoided this whole mess. Sebastian has suffered for your decision, Ciel. Now, if you will please follow me."

Alois gestured to a door at the back of the room. Ciel narrowed his eye at the deranged boy. This was obviously some sort of trap.

"Don't-" Sebastian tried to warn him, but was cut off when Claude grabbed his throat with his free hand.

Sebastian's bound hands clawed at the hand around his throat, trying to release the pressure that was nearly crushing it.

"Fine," came Ciel's curt reply.

He hadn't intentionally meant to sound so cold, but he thought Claude would stop hurting Sebastian if he agreed quickly. The young earl motioned for Undertaker and Grell to follow him, but Alois put up a hand.

"I'm afraid your friends will have to remain out here," he said.

"And I'm afraid I can't allow that," Undertaker spoke up.

The legendary reaper unclipped the chain he wore around his waist, allowing him access to his hidden sotoba. He aimed the first straight at Alois. The Trancy butler sprung into action to block Undertaker's attack.

Undertaker shielded Ciel behind him as he launched more sotoba at the other demonic servants. The young earl peeked out from behind his informant to search for his butler. Much to his dismay, he saw Alois leaving the fight, Gwenna following and dragging Sebastian along behind her.

Despite the fact that he was fighting, Undertaker noticed this as well.

"Go find your butler. Grell, go with him."

Ciel didn't need to be told twice. He darted out from behind Undertaker, Grell right on his heels. The other demons were so preoccupied with Undertaker that they didn't have a chance to touch the other two as they rushed across the room to follow Alois.

Once Ciel opened the door, he noticed the trail of blood. He glanced back at his informant. He had to trust that he could hold his own against the demonic servants. Grell gulped at the sight of all the blood, not liking the fact that it had all come from Sebastian. If Ciel were honest with himself, he didn't like it either.

He took a deep breath, then ran along the bloody trail. He needed to find Sebastian.

 **And there's the fourth chapter! I hope you all enjoyed it! What's Gwenna going to do now that things aren't going quite as planned? Find out next chapter! Until then!**


	5. Chapter 5

**Hello! I'm back with another chapter! Sorry for the long updates between these chapters. Since this is the last one to this short little tale, I just had a lot of difficulty getting it just how I wanted it. Anyways, on with the story!**

 **I do not own Kuroshitsuji.**

Sebastian's vision blurred as Gwenna dragged him away. Every slice and stab wound inflicted on him screamed in agony and he could feel blood continuing to stream from his wounds. He could vaguely hear Alois say something to Gwenna, but he didn't have the slightest idea of what he could be saying.

He let out a pained groan when he was suddenly dropped on the ground. Gwenna straddled him, leaning down until her lips were right next to his ear.

"Looks like we're running out of time," she hissed in his ear.

He was barely coherent enough to realize what she meant. Fiery pain coursed through his body as she started carving a pentagram into his chest.

"No!" he breathed.

She was carving her contract mark into him. For the first time in centuries, the Phantomhive butler was truly scared. He was going to be bound to the archdemon for eternity if she completed the ritual. A demonic smile possessed her face as soon as she finished. She held out a vial, making sure he could see it.

Gwenna uncapped it and pushed it toward him, but he turned his head to the side. He knew the second the potion inside made it down his throat, the bond between him and Gwenna would start forming.

"Why do you have to make this so difficult?" she asked.

Sebastian felt two hands grab his face, forcing him back toward the archdemon. What he didn't expect was for Gwenna's lips to crash down onto his. She immediately dug her fingers into the fresh carving on his chest, causing him to gasp in pain.

That's when he felt the potion in his mouth and flowing down his throat. He tried in vain to push Gwenna away. He could feel her slightly smirk into the kiss. She was enjoying his futile struggles, knowing now that there was nothing he could do.

Suddenly, the weight on him disappeared and Sebastian saw a red blur flash before his eyes.

"Sebastian!"

The Phantomhive butler barely heard someone calling his name. Fire coursed through his veins as his eyes and the carving slowly started to glow.

Ciel sprinted toward his butler the second Grell tackled Gwenna off of him, but he was stopped when something crashed down on his head. He turned over and saw a blurry Alois standing over him, sword in hand.

"Looks like you will finally be mine, Ciel Phantomhive." The deranged boy straddled Ciel and pressed the flat of the blade against his throat. "I know how badly Sebastian wanted to devour your soul, but he won't get to. I'm going to rip your soul to shreds while he can do nothing but watch as Gwenna's eternal slave."

At the mention of his butler, Ciel risked a quick glance over at the demon. His back was arching as the pentagram carved in his chest glowed brighter and brighter. Suddenly, the sword pressed against his throat was gone and Alois had it poised with the tip against his chest.

He wanted to wipe that cocky smirk off his face.

"Stop your futile struggling, Ciel. Just submit to me!"

He brought the sword up then back down to pierce Ciel's chest, but gasped when his victim gripped the blade. Blood was running down Ciel's hand, but he kept the sword in place.

"Someone like you could never afford to even taste my soul," Ciel chuckled darkly.

A screech resounded throughout the room, grabbing the attention of both earls. Undertaker and Grell watched as Gwenna was consumed in flames. When had Undertaker gotten here? Actually, Ciel wasn't going to question it. This was just what he needed.

"G-Gwenna?" Alois stammered as he watched the archdemon being pulled back to hell.

Using the distraction to his advantage, Ciel grabbed the blade with both hands and yanked it out of the boy's grasp. He flipped the sword around and impaled it through Alois. Once he pulled it out, the shocked earl fell to his side, clutching his bleeding stomach. His hysterical cries went unheard by Ciel as he rushed to his butler.

A tormented scream ripped itself from Sebastian's throat. The agony was too much to bear. He could feel himself getting pulled down to hell along with Gwenna. Instantly, Undertaker was by the young earl's side.

Gwenna's screams had stopped.

Ciel looked around. There was no sign of the archdemon anywhere.

"Grell, sit him up," the ancient reaper ordered.

That snapped Ciel's attention back to his butler. Grell put an arm under Sebastian's mutilated back, slightly raising him up. Undertaker raked his long nails across his wrist.

"What are you doing?" Ciel demanded when Undertaker put his now bloody wrist against Sebastian's lips.

The Phantomhive butler gave a muffled cry of alarm when he tasted the reaper's blood.

"Drink," Undertaker encouraged as he cupped his hand behind Sebastian's head, preventing him from turning away.

With no other choice, the demon drank Undertaker's blood. The ancient reaper pulled his wrist away.

Ciel watched with wide eyes as his butler managed to tear himself free of Grell's grasp and throw up the blood that was just forced down his throat. He saw Sebastian collapse on his side, his eyes drooping shut.

The glow of the pentagram started to fade.

"The blood of a reaper is toxic to a demon," Undertaker explained. "Too much would have killed him, but I had him drink just enough so he would hopefully throw up the potion that was binding him to Gwenna." He cocked his head to the side when the pentagram grew completely dark. "It seems to have worked."

"Help me, Claude!" Alois's frantic scream rang throughout Trancy manor.

Undertaker and Grell freed the unconscious demon from his bindings. The ancient reaper slipped his arms under Sebastian's back and legs, lifting him up with a strength that surprised Ciel. He turned to the young boy.

"We should get you back to your manor, young Earl."

 ***break***

Sebastian barely suppressed a pained groan as he returned to consciousness. He had to blink a few times as he saw his new surroundings.

He was in his bedroom at Phantomhive manor. The curtains were closed, but he could see the dark orange light of a sunset peeking into the room. He had been propped up against the pillows on his bed with a blanket pulled up to his waist. He looked down to find his stomach and chest were covered in bandages. Someone had dressed him in a black sleep shirt and pants, keeping the buttons of the shirt undone.

His head snapped up at the sound of soft snoring.

Even in the dim lighting, he could make out the small form of Ciel in a chair next to him. He was hunched over, lying face down on the bed.

"He has yet to leave your side since we brought you back last night."

The Phantomhive butler looked to the other side of the bed. He could see the ghostly hair of Undertaker.

"I tried to get him to go to his room to rest, but he refused."

Sebastian looked back to the sleeping boy.

"Why did you save me?" he asked, his voice slightly scratchy as opposed to its usual smoothness.

He didn't understand. Reapers and demons were enemies. Undertaker had absolutely no reason to save him from being bound to Gwenna.

If anything, he should have allowed it to happen.

"I personally prefer neither to side or oppose demons," the ancient reaper said softly, as not to wake the young earl, "but I should have been more careful when I first found Gwenna. I should have known that a demon that powerful would only have business to do with you. That was carelessness on my part."

Sebastian's brow furrowed. It still didn't make sense.

"At least for now, you protect Earl Phantomhive," he went on to explain. "You help him fulfill his duties as the Queen's Guard Dog. I had to allow that to continue for the time being."

The demon's eyes widened in realization. Ciel had to continue his father's work. From what he understood, Undertaker had been an informant of the Phantomhive's for quite some time. Of course he would want Ciel to continue his to fulfill duties for the Queen.

"What happened to Alois and his staff?" he asked next.

Undertaker shrugged fluidly.

"Once the contract forming between you and Gwenna was broken, we left immediately. Last I saw, Alois was about to bleed out from the Earl's stab wound if his butler didn't recover and take care of him. Grell and I have remained here to guard the manor until you awoke should they have decided to retaliate. Grell asked if I would get him after you woke up. I'm sure he wants to help redress your wounds."

Sebastian looked back down at his bandages, now noticing the splotches of red peeking through the cloth. He wanted to protest, but he couldn't deny that he would probably need help in his state. He rolled his eyes when he saw an amused smile play at the reaper's lips. Grell would be all too happy to help, and they both were completely aware of that. He watched as Undertaker moved to leave.

"How can I thank you?" he asked, making the ancient reaper stop in his tracks.

The amused smile turned cold as Undertaker turned to face him. His bangs moved to the side, revealing an equally cold eye.

"I wouldn't worry about that if I were you. There may come a day when you won't be thanking me."

Sebastian would be lying if he said that didn't send chills down his spine when the reaper left. Undertaker may have approved what he was doing now to protect Earl Phantomhive, but that didn't mean he was keen on the idea of him eventually consuming Ciel's soul.

He looked at the boy next to him. Even though he was a demon, he couldn't help but be touched by the fact that Ciel had stayed by his side.

He's met thousands of humans throughout his existence, but none of them stood out quite like Ciel Phantomhive.

He too was ready to remain by his side until he finally accomplished what his soul desired.

 **And there it is! I hope you all enjoyed this short little fic! I basically just wanted an excuse to torture Sebastian, and it was quite fun to write. I especially loved foreshadowing the slightly darker turn Undertaker takes in the manga.**

 **Anyways, I'm apologize again for the random updates in chapters. Life just gets crazy and some stories are just easier to write than others. I have a couple fic ideas regarding Undertaker, so I hope to start those soon in the near future.**

 **Again, thank you all for reading! I hope you all found this to be an entertaining read!**

 **Until next time,**

 **alightintheshadows**


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